Cyanide With Compliments is the fifth in the Tom Pollard/Gregory Toye series by Elizabeth Lemarchand. It has dropped to $0.99/£0.99 at Kindle US/UK, as a Countdown deal good for about 6 more days.
Kindle US:
https://www.amazon.com/gp/product/B07K6V7Y3G
Kindle US/Smile:
https://smile.amazon.com/gp/product/B07K6V7Y3G
Kindle UK:
https://www.amazon.co.uk/gp/product/B07K6V7Y3G
Kindle UK/Smile:
https://smile.amazon.co.uk/gp/product/B07K6V7Y3G
The first three titles in this series have previously been Countdown deals (making me wonder if I missed the fourth one), but the first is also still at $0.99/£0.99 if you want to try the first one first. Info and links in this previous post:
https://www.mobileread.com/forums/sh....php?p=3856560